page_in values in vmstat output

We are facing general dissatisfaction among the users about the system response time and overall performance of the application.

When we ran the vmstat command on the Sun Solaris Server, we observed non-zero values in the page_in column of the output, and we suspect that this is one of the reasons for the poor performance.

Availability of RAM.

$ prtconf|grep Memory
Memory size: 7168 Megabytes

Time|Average runque_waits|page_ins from vmstat output.

TIME               Runque Page_in 
1/22/03 9:45:14 AM 0      12830 
1/22/03 9:40:13 AM 0      15163 
1/22/03 9:35:13 AM 0      13938 
1/22/03 9:30:13 AM 0      17692 
1/22/03 9:25:12 AM 0      16095 
1/22/03 9:20:12 AM 0      14986 
1/22/03 9:15:12 AM 0      15324 
1/22/03 9:10:11 AM 0      18675 
1/22/03 9:05:11 AM 0      19822 
1/22/03 9:00:11 AM 0      12061 
1/22/03 8:55:10 AM 0      10130 
1/22/03 8:50:10 AM 0      15357 

However the percentage of total sga's of the 4 dbs(1.3GB) running on this server is only 18% of the total RAM (7GB) available on this server. This server is not having any applications on it execept these 4 database servers. Users will connect thorough a CITRIX application server.

1st Database
SQL> conn sys
Connected.
SQL> show sga;

Total System Global Area 753217696 bytes Fixed Size 73888 bytes
Variable Size 664915968 bytes
Database Buffers 81920000 bytes
Redo Buffers 6307840 bytes

2nd Database
SQL> conn sys
Connected.
SQL> show sga;

Total System Global Area 354767008 bytes Fixed Size 73888 bytes
Variable Size 339472384 bytes
Database Buffers 13107200 bytes
Redo Buffers 2113536 bytes
3rd Database
SQL> conn sys
Connected.
SQL> show sga;

Total System Global Area 163115168 bytes Fixed Size 73888 bytes
Variable Size 77828096 bytes
Database Buffers 81920000 bytes
Redo Buffers 3293184 bytes

4th database
SQL> conn sys
Connected.
SQL> show sga;

Total System Global Area 78991520 bytes Fixed Size 73888 bytes
Variable Size 74551296 bytes
Database Buffers 2252800 bytes
Redo Buffers 2113536 bytes

We are not able to understand why the server is paging when around 80% of the RAM is not reserved for any other application.

Our server is heavily IO bound and IO is not distributed equally among the 16 disks available in this server. Does this fact has any remote connection with our above problem.

Is this a common phenomenon or am I missing some thing here?. Received on Sun Feb 09 2003 - 11:49:09 CST